[20190417]隐含参数_SPIN_COUNT.txt
[20190417]隐含参数_SPIN_COUNT.txt
--//在探究latch spin计数之前,先简单探究_SPIN_COUNT.实际上oracle现在版本latch spin的数量不再是2000,而是记录在
--//x$ksllclass里面.通过例子说明:
1.环境:
SYS@book> @ ver1
PORT_STRING VERSION BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
SYS@book> select * from x$ksllclass ;
ADDR INDX INST_ID SPIN YIELD WAITTIME SLEEP0 SLEEP1 SLEEP2 SLEEP3 SLEEP4 SLEEP5 SLEEP6 SLEEP7
---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
00000000861986C0 0 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861986EC 1 1 20000 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198718 2 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
0000000086198744 3 1 20000 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198770 4 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
000000008619879C 5 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987C8 6 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987F4 7 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
8 rows selected.
SYS@book> select CLASS_KSLLT,count(*) from x$kslltr group by CLASS_KSLLT;
CLASS_KSLLT COUNT(*)
----------- ----------
2 1
0 581
SYS@book> select CLASS_KSLLT,decode(CLASS_KSLLT,2,KSLLTNAM) name,count(*) from x$kslltr group by CLASS_KSLLT,decode(CLASS_KSLLT,2,KSLLTNAM);
CLASS_KSLLT NAME COUNT(*)
----------- ------------------ --------
0 581
2 process allocation 1
--//还可以看出仅仅1个latch属于2类(latch name='process allocation').其它都是0类.实际上即使是0类,后面的SLEEP0-7不再使用.
--//可以发现缺省全部SPIN=20000.
2.测试1:
SYS@book> alter system set "_spin_count"=200 scope=memory;
System altered.
--//实际上动态修改无效.重新登录会话:
SYS@book> select * from x$ksllclass ;
ADDR INDX INST_ID SPIN YIELD WAITTIME SLEEP0 SLEEP1 SLEEP2 SLEEP3 SLEEP4 SLEEP5 SLEEP6 SLEEP7
---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
00000000861986C0 0 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861986EC 1 1 20000 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198718 2 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
0000000086198744 3 1 20000 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198770 4 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
000000008619879C 5 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987C8 6 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987F4 7 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
8 rows selected.
--//SPIN数量不变.实际上动态修改,对应exclusive latch无效.仅仅对shared latch有效,导致实际spin 数量等于_spin_count*2.(我当前没有测试)
--//参考链接:http://andreynikolaev.wordpress.com/2011/01/14/spin-tales-part-2-shared-latches-in-oracle-9-2-11g/
3.测试2:
SYS@book> alter system set "_spin_count"=200 scope=spfile ;
System altered.
--//重启数据库观察:
SYS@book> select * from x$ksllclass ;
ADDR INDX INST_ID SPIN YIELD WAITTIME SLEEP0 SLEEP1 SLEEP2 SLEEP3 SLEEP4 SLEEP5 SLEEP6 SLEEP7
---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
00000000861986C0 0 1 200 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861986EC 1 1 200 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198718 2 1 200 0 1 8000 8000 8000 8000 8000 8000 8000 8000
0000000086198744 3 1 200 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198770 4 1 200 0 1 8000 8000 8000 8000 8000 8000 8000 8000
000000008619879C 5 1 200 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987C8 6 1 200 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987F4 7 1 200 0 1 8000 8000 8000 8000 8000 8000 8000 8000
8 rows selected.
--//这样更改才生效.
SYS@book> alter system reset "_spin_count";
System altered.
--//实际上可以但是设置_latch_class_N参数.
SYS@book> alter system set "_latch_class_0"=1000 scope=spfile;
System altered.
--//重启数据库观察:
SYS@book> select * from x$ksllclass ;
ADDR INDX INST_ID SPIN YIELD WAITTIME SLEEP0 SLEEP1 SLEEP2 SLEEP3 SLEEP4 SLEEP5 SLEEP6 SLEEP7
---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
00000000861986C0 0 1 1000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861986EC 1 1 20000 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198718 2 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
0000000086198744 3 1 20000 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198770 4 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
000000008619879C 5 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987C8 6 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987F4 7 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
8 rows selected.
--//你甚至指定特定的latch采用特定的类.还可以修改后面的YIELD,WAITTIME,SLEEP0-SELLP7值.例子:
*._latch_classes='8:3'
*._latch_class_3='100 0 1 10000 20000 30000 40000 50000 60000 70000 80000'
SYS@book> select * from v$latchname where name='process allocation';
LATCH# NAME HASH
---------- ---------------------------------------- ----------
8 process allocation 2600548697
--//_latch_classes 里面8 值LATCH#,后面3值类.可以指定多个,例子:
--//alter system set "_latch_classes"='46:3 103:3' scope=spfile;
--//还原:
SYS@book> alter system reset "_latch_class_0";
System altered.
4.加强记忆我找一个latch测试看看:
--//上午测试是process allocation,现在测试看看类0的修改是否有效.
select addr,name,level#,latch#,gets,misses,sleeps,immediate_gets,immediate_misses,waiters_woken,waits_holding_latch,spin_gets,wait_time from v$latch_parent where lower(name) like '%'||lower('test excl. parent l0')||'%'
ADDR NAME LEVEL# LATCH# GETS MISSES SLEEPS IMMEDIATE_GETS IMMEDIATE_MISSES WAITERS_WOKEN WAITS_HOLDING_LATCH SPIN_GETS WAIT_TIME
---------------- ---------------------------------------- ---------- ---------- ---------- ---------- ---------- -------------- ---------------- ------------- ------------------- ---------- ----------
00000000600098D8 test excl. parent l0 0 4 7 0 0 0 0 0 0 0 0
--//LATCH#=4.
SYS@book> create pfile='/tmp/@.ora' from spfile ;
File created.
--//修改/tmp/book.ora 加入:
*._latch_classes='4:3'
*._latch_class_3='100 0 1 10000 20000 30000 40000 50000 60000 70000 50000'
SYS@book> startup pfile=/tmp/@.ora
ORACLE instance started.
Total System Global Area 643084288 bytes
Fixed Size 2255872 bytes
Variable Size 205521920 bytes
Database Buffers 427819008 bytes
Redo Buffers 7487488 bytes
Database mounted.
Database opened.
SYS@book> select * from x$ksllclass ;
ADDR INDX INST_ID SPIN YIELD WAITTIME SLEEP0 SLEEP1 SLEEP2 SLEEP3 SLEEP4 SLEEP5 SLEEP6 SLEEP7
---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
00000000861986C0 0 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861986EC 1 1 20000 0 1 1000 1000 1000 1000 1000 1000 1000 1000
0000000086198718 2 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
0000000086198744 3 1 100 0 1 10000 20000 30000 40000 50000 60000 70000 50000
0000000086198770 4 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
000000008619879C 5 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987C8 6 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
00000000861987F4 7 1 20000 0 1 8000 8000 8000 8000 8000 8000 8000 8000
8 rows selected.
SYS@book> select CLASS_KSLLT,decode(CLASS_KSLLT,2,KSLLTNAM,3,KSLLTNAM) name,count(*) from x$kslltr group by CLASS_KSLLT,decode(CLASS_KSLLT,2,KSLLTNAM,3,KSLLTNAM);
CLASS_KSLLT NAME COUNT(*)
----------- ---------------------------------------- ----------
0 580
3 test excl. parent l0 1
2 process allocation 1
--//latch_name='test excl. parent l0',CLASS_KSLLT=3.
$ cat p4.sh
#! /bin/bash
vdate=$(date '+%H%M%S')
echo $vdate
source peek.sh "$1" 20 | timestamp.pl >| /tmp/peekx_${vdate}.txt &
sqlplus -s -l / as sysdba <<EOF >| /tmp/latch_free_${vdate}.txt &
$(seq 20 | xargs -I {} echo -e '@latch_free \n host sleep 1')
EOF
sleep 1
# 参数如下: @ exclusive_latch.txt latch_name willing why where sleep_num
sqlplus /nolog @ exclusive_latch.txt "$1" 1 4 5 10 > /dev/null &
sleep 2
sqlplus /nolog @ exclusive_latch.txt "$1" 1 6 7 10 > /dev/null &
p=$!
strace -ftrT -p $p -o /tmp/pp_${vdate}.txt > /dev/null &
wait
$ . p4.sh 'test excl. parent l0'
172843
Process 29626 attached - interrupt to quit
Process 29628 attached
Process 29645 attached
Process 29626 suspended
[1] Done source peek.sh "$1" 20 | timestamp.pl >|/tmp/peekx_${vdate}.txt
[3] Done sqlplus /nolog @ exclusive_latch.txt "$1" 1 4 5 10 > /dev/null
[2] Done sqlplus -s -l / as sysdba >|/tmp/latch_free_${vdate}.txt <<EOF
$(seq 20 | xargs -I {} echo -e '@latch_free \n host sleep 1')
EOF
Process 29626 resumed
Process 29645 detached
Process 29626 detached
[4]- Done sqlplus /nolog @ exclusive_latch.txt "$1" 1 6 7 10 > /dev/null
Process 29628 detached
[5]+ Done strace -ftrT -p $p -o /tmp/pp_${vdate}.txt > /dev/null
--// /tmp/pp_172843.txt
29628 0.000081 write(10, "\n", 1) = 1 <0.000026>
29628 0.000149 select(0, [], [], [], {0, 10000}) = 0 (Timeout) <0.010082>
29628 0.010161 select(0, [], [], [], {0, 20000}) = 0 (Timeout) <0.020110>
29628 0.020195 select(0, [], [], [], {0, 30000}) = 0 (Timeout) <0.030115>
29628 0.030207 select(0, [], [], [], {0, 40000}) = 0 (Timeout) <0.040118>
29628 0.040216 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050120>
29628 0.050209 select(0, [], [], [], {0, 60000}) = 0 (Timeout) <0.060129>
29628 0.060218 select(0, [], [], [], {0, 70000}) = 0 (Timeout) <0.070140>
29628 0.070230 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050124>
29628 0.050213 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050118>
29628 0.050207 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050124>
29628 0.050216 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050134>
29628 0.050224 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050117>
29628 0.050207 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050120>
29628 0.050209 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050117>
29628 0.050206 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050120>
29628 0.050211 select(0, [], [], [], {0, 50000}) = 0 (Timeout) <0.050125>
--//可以发现一样有效.
$ awk '/select/ {print $NF}' /tmp/pp_172843.txt | tr -d '<>' | xargs | sed 's/ /+/g' | bc -l
7.899805
--//接近8秒.spin占用时间不多.
[20190417]隐含参数_SPIN_COUNT.txt的更多相关文章
- [20190401]隐含参数_mutex_spin_count.txt
[20190401]隐含参数_mutex_spin_count.txt --//上午做了一些测试关于semtimedop函数调用,发现自己上个星期在一些问题上理解错误.--//相关链接:--//htt ...
- [20191206]隐含参数_db_always_check_system_ts.txt
[20191206]隐含参数_db_always_check_system_ts.txt --//今年年头我做tab$删除恢复时,遇到的问题,就是遇到延迟块清除的问题.参考链接:http://blog ...
- [20181108]12c sqlplus rowfetch参数4.txt
[20181108]12c sqlplus rowfetch参数4.txt --//12cR2 可以改变缺省rowfetch参数.11g之前缺省是1.通过一些测试说明问题.--//前几天做的测试有点乱 ...
- 转 rman-08120 以及查询隐含参数
rman-08120 We need RMAN to automatically purge archivelogs from the FRA once they are applied to the ...
- js的隐含参数(arguments,callee,caller)使用方法
在提到上述的概念之前,首先想说说javascript中函数的隐含参数: arguments arguments 该对象代表正在执行的函数和调用它的函数的参数.[function.]arguments[ ...
- paip.提升性能---mysql 性能 测试以及 参数调整.txt
paip.提升性能---mysql 性能 测试以及 参数调整.txt 作者Attilax 艾龙, EMAIL:1466519819@qq.com 来源:attilax的专栏 地址:http://b ...
- paip.提升性能----jvm参数调整.txt
paip.提升性能----jvm参数调整.txt 作者Attilax 艾龙, EMAIL:1466519819@qq.com 来源:attilax的专栏 地址:http://blog.csdn.n ...
- 传递给函数的隐含参数：arguments及递归函数的实现
传递给函数的隐含参数:arguments当进行函数调用时,除了指定的参数外,还创建一个隐含的对象——arguments.arguments是一个类似数组但不是数组的对象,说它类似是因为它具有数组一样的 ...
- [20170927]hugepages与内核参数nr_overcommit_hugepages.txt
[20170927]hugepages与内核参数nr_overcommit_hugepages.txt /proc/sys/vm/nr_overcommit_hugepages specifies h ...
随机推荐
- Java 在PDF 中添加超链接
对特定元素添加超链接后,用户可以通过点击被链接的元素来激活这些链接,通常在被链接的元素下带有下划线或者以不同的颜色显示来进行区分.按照使用对象的不同,链接又可以分为:文本超链接,图像超链接,E-mai ...
- 简单地做一下“回到顶部”按钮，用jQuery实现其隐藏和显示
1.首先,我们要准备HTML代码: <div id="return-top"> <a href="#top">返回顶部</a> ...
- K3数据字典备查
select distinct f.FNumber as 系统代码, f.FName AS 系统名称, d.FTableName AS 表名,d.FDescription AS 表说明,a.[nam ...
- IconFont的iOS使用
IconFont的使用 Iconfont-国内功能很强大且图标内容很丰富的矢量图标库,提供矢量图标下载.在线存储.格式转换等功能.阿里巴巴体验团队倾力打造,设计和前端开发的便捷工具. https:// ...
- June 30th. 2018, Week 26th. Saturday
Curiosity is the wick in the candle of learning. 如果学习是一根蜡烛,那好奇心就是烛芯. From William Arthur Ward. Pleas ...
- SQL注入攻击的常见方式及测试方法
本文主要针对SQL注入的含义.以及如何进行SQL注入和如何预防SQL注入让小伙伴有个了解.适用的人群主要是测试人员,了解如何进行SQL注入,可以帮助我们测试登录.发布等模块的SQL攻击漏洞,至于如何预 ...
- Python中的音频和数字信号处理（DSP）
翻译自Python For Engineers. 1. 创建一个正弦波 在这个项目中,我们将创建一个正弦波,并将其保存为wav文件. 但在此之前,你应该知道一些理论. 频率:频率是正弦波重复一秒的次数 ...
- 一份非常完整的MySQL规范
一.数据库命令规范 所有数据库对象名称必须使用小写字母并用下划线分割 所有数据库对象名称禁止使用mysql保留关键字(如果表名中包含关键字查询时,需要将其用单引号括起来) 数据库对象的命名要能做到见名 ...
- 三种方式实现观察者模式 及 Spring中的事件编程模型
观察者模式可以说是众多设计模式中,最容易理解的设计模式之一了,观察者模式在Spring中也随处可见,面试的时候,面试官可能会问,嘿,你既然读过Spring源码,那你说说Spring中运用的设计模式吧, ...
- Activity、Fragment、Dialog基类简单整理
版权声明:本文为HaiyuKing原创文章,转载请注明出处! 概述 这里简单记录下Activity.Fragment.Dialog基类中的常规写法,后续根据项目需求进行相应的扩展. BaseActiv ...